Ongoing haemolytic uraemic syndrome (HUS) outbreak caused by sorbitol-fermenting (SF) Shiga toxin-producing Escherichia coli (STEC) O157, Germany, December 2016 to May 2017

Environmental Change, Changing Biodiversity, and Infections-Lessons for Kidney Health Community

There is a direct and accelerating connection between ongoing environmental change, the unprecedented decline in biodiversity, and the increase in infectious disease epidemiology worldwide. Rising global temperatures are threatening the biodiversity that underpins the richness and diversity of flora and fauna species in our ecosystem. Anthropogenic activities such as burning fossil fuels, deforestation, rapid urbanization, and expanding population are the primary drivers of environmental change resulting in biodiversity collapse. Climate change is influencing the emergence, prevalence, and transmission of infectious diseases both directly and through its impact on biodiversity. The environment is gradually becoming more suitable for infectious diseases by affecting a variety of pathogens, hosts, and vectors and by favoring transmission rates in many parts of the world that were until recently free of these infections. The acute effects of these zoonotic, vector and waterborne diseases are well known; however, evidence is emerging about their role in the development of chronic kidney disease. The pathways linking environmental change and biodiversity loss to infections impacting kidney health are diverse and complex. Climate change and biodiversity loss disproportionately affect the vulnerable and limit their ability to access healthcare. The kidney health community needs to contribute to the issue of environmental change and biodiversity loss through multisectoral action alongside government, policymakers, advocates, businesses, and the general population. We describe various aspects of the environmental change effects on the transmission and emergence of infectious diseases particularly focusing on its potential impact on kidney health. We also discuss the adaptive and mitigation measures and the gaps in research and policy action.

An appeal for strengthening genomic pathogen surveillance to improve pandemic preparedness and infection prevention: the German perspective

The SARS-CoV-2 pandemic has highlighted the importance of viable infection surveillance and the relevant infrastructure. From a German perspective, an integral part of this infrastructure, genomic pathogen sequencing, was at best fragmentary and stretched to its limits due to the lack or inefficient use of equipment, human resources, data management and coordination. The experience in other countries has shown that the rate of sequenced positive samples and linkage of genomic and epidemiological data (person, place, time) represent important factors for a successful application of genomic pathogen surveillance. Planning, establishing and consistently supporting adequate structures for genomic pathogen surveillance will be crucial to identify and combat future pandemics as well as other challenges in infectious diseases such as multi-drug resistant bacteria and healthcare-associated infections. Therefore, the authors propose a multifaceted and coordinated process for the definition of procedural, legal and technical standards for comprehensive genomic pathogen surveillance in Germany, covering the areas of genomic sequencing, data collection and data linkage, as well as target pathogens. A comparative analysis of the structures established in Germany and in other countries is applied. This proposal aims to better tackle epi- and pandemics to come and take action from the "lessons learned" from the SARS-CoV-2 pandemic.

Antimicrobial Activity of Sorghum Phenolic Extract on Bovine Foodborne and Mastitis-Causing Pathogens

Antimicrobial resistance in bacterial pathogens associated with bovine mastitis and human foodborne illnesses from contaminated food and water have an impact on animal and human health. Phenolic compounds have antimicrobial properties and some specialty sorghum grains are high in phenolic compounds, and the grain extract may have the potential as a natural antimicrobial alternative. The study’s objective was to determine antimicrobial effects of sorghum phenolic extract on bacterial pathogens that cause bovine mastitis and human foodborne illnesses. Bacterial pathogens tested included Escherichia coli, Salmonella Typhimurium, Campylobacter jejuni, Campylobacter coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Klebsiella oxytoca, Staphylococcus aureus, and Enterococcus faecalis. Antibacterial activities of sorghum phenolic extracts were determined by agar-well diffusion assay. Sorghum phenolic extract was added to the wells in concentrations of 0, 100, 200, 500, 1000, or 4000 µg/mL. The control wells did not receive phenolic extract. Plates were incubated for 18–24 h, and the diameter of each zone of inhibition was measured. The results indicated that sorghum phenolic extract had inhibitory effects on Staphylococcus aureus, Enterococcus faecalis, Campylobacter jejuni, and Campylobacter coli.

Shiga Toxin-Producing E. coli in Animals: Detection, Characterization, and Virulence Assessment

Cattle and other ruminants are primary reservoirs for Shiga toxin-producing Escherichia coli (STEC) strains which have a highly variable, but unpredictable, pathogenic potential for humans. Domestic swine can carry and shed STEC, but only STEC strains producing the Shiga toxin (Stx) 2e variant and causing edema disease in piglets are considered pathogens of veterinary medical interest. In this chapter, we present general diagnostic workflows for sampling livestock animals to assess STEC prevalence, magnitude, and duration of host colonization. This is followed by detailed method protocols for STEC detection and typing at genetic and phenotypic levels to assess the relative virulence exerted by the strains.

Shiga toxin-producing Escherichia coli O26:H11 associated with a cluster of haemolytic uraemic syndrome cases in South Africa, 2017

INTRODUCTION

Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that may cause diarrhoeal outbreaks and occasionally are associated with haemolytic-uraemic syndrome (HUS). We report on STEC O26:H11 associated with a cluster of four HUS cases in South Africa in 2017.

METHODOLOGY

All case-patients were female and aged 5 years and under. Standard microbiological tests were performed for culture and identification of STEC from specimens (human stool and food samples). Further analysis of genomic DNA extracted from bacterial cultures and specimens included PCR for specific virulence genes, whole-genome sequencing and shotgun metagenomic sequencing.

RESULTS

For 2/4 cases, stool specimens revealed STEC O26:H11 containing eae, stx2a and stx2b virulence genes. All food samples were found to be negative for STEC. No epidemiological links could be established between the HUS cases. Dried meat products were the leading food item suspected to be the vehicle of transmission for these cases, as 3/4 case-patients reported they had eaten this. However, testing of dried meat products could not confirm this.

CONCLUSION

Since STEC infection does not always lead to severe symptoms, it is possible that many more cases were associated with this cluster and largely went unrecognized.

Plasmid-Mediated Colistin Resistance in Escherichia coli O157:H7 Cattle and Sheep Isolates and Whole-Genome Sequence of a Colistin-Resistant Sorbitol Fermentative Escherichia coli O157:H7

The aims of this study were to investigate the plasmid-mediated colistin resistance genes (mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5), phenotypic colistin resistance in Escherichia coli O157:H7⁺/H7^- strains isolated from cattle and sheep, and whole-genome sequence (WGS) analysis of colistin-resistant sorbitol fermentative E. coli O157:H7. According to the results, 5 of the 49 isolates were found to harbor mcr-2 and/or mcr-3 genes. Three isolates, including a sorbitol fermentative E. coli O157:H7, were found phenotypically resistant to colistin with a minimum inhibitory concentration value of 128 μg/mL. The genome of sorbitol fermentative E. coli O157:H7 did not show 100% similarity to any of the other genome sequences found in the universal genome database. It has also been determined that this isolate carried 62 different antimicrobial resistance genes. This is the first report of plasmid-mediated mcr-2 and mcr-3 genes carrying E. coli O157:H7 from cattle and sheep isolates and WGS of a colistin-resistant sorbitol fermentative E. coli O157:H7. Findings of this study indicate that cattle and sheep can be an important source of colistin resistance in E. coli O157:H7, and slaughterhouse wastewater might be a significant route for dissemination of the plasmid-mediated colistin genes. Therefore, the use of colistin in veterinary medicine should be restricted to reduce the development of resistance. Also it may be necessary to review the non-sorbitol fermentation-based isolation protocol for not missing the sorbitol fermentative E. coli O157:H7 in epidemiological studies.

The Antimicrobial Effect of a Commercial Mixture of Natural Antimicrobials Against Escherichia coli O157:H7

Ruminants are important reservoirs of E. coli O157:H7 and are considered as the major source of most foodborne outbreaks (e.g., 2017 outbreak in Germany, 2014 and 2016 outbreaks in United States, all linked to beef products). A promising strategy to reduce E. coli O157 is using antimicrobials to reduce the pathogen levels and/or virulence within the animal gastrointestinal tract and thus foodborne disease. The aim of the study was to determine the efficacy of a commercial mixture of natural antimicrobials against E. coli O157. The minimum inhibitory concentration and minimum bactericidal concentration of the antimicrobial were quantitatively determined and found to be 0.5% and 0.75% (v/v) of the natural antimicrobial, respectively. Microbial growth kinetics was also used to determine the effect of the antimicrobial on the pathogen. The natural antimicrobial affected the cell membrane of E. coli O157, as demonstrated by the increase in relative electric conductivity and increase in protein and nucleic acid release. The antimicrobial was also able to significantly reduce the concentration on E. coli O157 in a model rumen system. Biofilm assays showed that subinhibitory concentrations of the antimicrobial significantly reduced the E. coli 0157 biofilm forming capacity without influencing pathogen growth. In addition, the natural antimicrobial was able to reduce motility and exopolysaccharide production. Subinhibitory concentrations of the antimicrobial had no effect on AI-2 production. These findings suggest that the natural antimicrobial exerts an antimicrobial effect against E. coli O157 in vitro and in a model rumen system and could be potentially used to control this pathogen in the animal gut. The results also indicate that subinhibitory concentrations of the antimicrobial effectively reduce biofilm formation, motility, and exopolysaccharide production.

Haemolytic uremic syndrome surveillance in children less than 15 years in Belgium, 2009-2015

Background

The Haemolytic Uremic Syndrome (HUS) is the most severe manifestation of infection with Shiga toxin-producing Escherichia coli (STEC). In Belgium, the surveillance of paediatric HUS cases is conducted by a sentinel surveillance network of paediatricians called Pedisurv. In this article, we present the main findings of this surveillance from 2009 to 2015 and we describe an annual incidence of HUS.

Methods

For each case of HUS <  15 years notified by the paediatricians, clinical, microbiological and epidemiological data were collected by a questionnaire. National hospital discharge data with ICD-9 code 283.11 were used to calculate the incidence of HUS in children < 15 years.

Results

From 2009 to 2015, 110 cases were notified to the Pedisurv network with a mean annual notification rate of 0.8/100,000 in children < 15 years. Death occurred in 2.5% of all patients and the median number of days of hospitalization was 10 days. One third (35.4%) of the HUS cases were confirmed positive STEC, with a majority of STEC O157. The mean annual incidence based on the hospital discharge data was 3.2/100,000 in children < 15 years and 4.5/100,000 in children < 5 years.

Conclusion

The incidence of paediatric HUS in Belgium is high compared to other European countries. Its surveillance in Belgium is quite comprehensive and, although less effective than monitoring all STEC infections to detect the emergence of outbreaks, is important to better monitor circulation of the most pathogenic STEC strains. In this context, efforts are still needed to send samples and STEC strains from HUS cases to the National Reference Centre.

Enterohemorrhagic Escherichia coli O157 outer membrane vesicles induce interleukin 8 production in human intestinal epithelial cells by signaling via Toll-like receptors TLR4 and TLR5 and activation of the nuclear factor NF-κB

Proinflammatory cytokines play important roles in the pathogenesis of diseases caused by enterohemorrhagic Escherichia coli (EHEC) O157, but the spectrum of bacterial components involved in the proinflammatory responses is not fully understood. Here, we investigated the abilities of outer membrane vesicles (OMVs), nanoparticles released by EHEC O157 during growth, to induce production of proinflammatory cytokines in human intestinal epithelial cells. OMVs from both EHEC O157:H7 and sorbitol-fermenting (SF) EHEC O157:H^- induced production of interleukin-8 (IL-8) in Caco-2, HCT-8, and HT-29 intestinal epithelial cell lines. H7 flagellin was the key IL-8-inducing component of EHEC O157:H7 OMVs, whereas cytolethal distending toxin V and O157 lipopolysaccharide (LPS) largely contributed to IL-8 production elicited by flagellin-lacking OMVs from SF EHEC O157:H^-. The H7 flagellin-mediated signaling via Toll-like receptor (TLR) 5, and O157 LPS-mediated signaling via TLR4/MD-2 complex, which were followed by activation of the nuclear factor NF-κB were major pathways underlying IL-8 production induced by EHEC O157 OMVs. The proinflammatory and immunomodulatory capacities of EHEC O157 OMVs have pathogenetic implications and support the OMVs as suitable vaccine candidates.

Sorbitol-Fermenting Enterohemorrhagic Escherichia coli O157:H- Isolates from Czech Patients with Novel Plasmid Composition Not Previously Seen in German Isolates

Sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:H^- strains, first identified in Germany, have emerged as important pathogens throughout Europe. Besides chromosomally encoded Shiga toxin 2a (the major virulence factor), several putative virulence loci, including the hly, etp, and sfp operons, encoding EHEC hemolysin, type II secretion system proteins, and Sfp fimbriae, respectively, are located on the 121-kb plasmid pSFO157 in German strains. Here we report novel SF EHEC O157:H^- strains isolated from patients in the Czech Republic. These strains share the core genomes and chromosomal virulence loci encoding toxins (stx_2a and the cdtV-ABC operon) and adhesins (eae-γ, efa1, lpfA_O157OI-141, and lpfA_O157OI-154) with German strains but differ essentially in their plasmids. In contrast to all previously detected SF EHEC O157:H^- strains, the Czech strains carry two plasmids, of 79 kb and 86 kb. The 79-kb plasmid harbors the sfp operon, but neither of the plasmids contains the hly and etp operons. Sequence analyses demonstrated that the 79-kb plasmid (pSFO157 258/98-1) evolved from pSFO157 of German strains by deletion of a 41,534-bp region via homologous recombination, resulting in loss of the hly and etp operons. The 86-kb plasmid (pSFO157 258/98-2) displays 98% sequence similarity to a 92.7-kb plasmid of an extraintestinal pathogenic E. coli bloodstream isolate. Our finding of this novel plasmid composition in SF EHEC O157:H^- strains extends the evolutionary history of EHEC O157 plasmids. Moreover, the unique molecular plasmid characteristics permit the identification of such strains, thereby facilitating further investigations of their geographic distribution, clinical significance, and epidemiology.IMPORTANCE Since their first identification in Germany in 1989, sorbitol-fermenting enterohemorrhagic Escherichia coli O157:H^- (nonmotile) strains have emerged as important causes of the life-threatening disease hemolytic-uremic syndrome in Europe. They account for 10 to 20% of sporadic cases of this disease and have caused several large outbreaks. The strains isolated throughout Europe share conserved chromosomal and plasmid characteristics. Here we identified novel sorbitol-fermenting enterohemorrhagic E. coli O157:H^- patient isolates in the Czech Republic which differ from all such strains reported previously by their unique plasmid characteristics, including plasmid number, composition of plasmid-carried virulence genes, and plasmid origins. Our findings contribute substantially to understanding the evolution of E. coli O157 strains and their plasmids. In practical terms, they enable the identification of strains with these novel plasmid characteristics in patient stool samples and thus the investigation of their roles as human pathogens in other geographic areas.